There are four quadrants in an x-y plane, Quadrant 1 consists of positive value of x and positive value of y: (+, +); Quadrant 2 consists of (-, +); Quadrant 3: (-,-); Quadrant 4: (+, -). If the x axis represents the number of hours, it should always have a positive value, and the y axis represents the temperature, it may be both positive and negative. So the possible quadrants are only quadrant 1 and 4.
